Method and apparatus for converting analog radio frequency (RF) signals to the digital domain in a multiband and multicarrier wireless communication system

ABSTRACT

Methods and systems are provided for converting wideband analog radio frequency (RF) signals. In an implementation, a first wideband analog RF signal may be received and handled. The first wideband analog RF signal comprises one or more first narrowband analog RF signals, with a total of bandwidths of the one or more first narrowband analog RF signals is less than a total bandwidth of the first wideband analog RF signal. Handling the first wideband analog RF signal may including selecting a first subset of analog-to-digital converters (ADCs) from a plurality of analog-to-digital converters (ADCs), with the number of ADCs in the first subset of ADCs being less than a total number of ADCs in the plurality of ADCs, and only the first subset of ADCs may be enabled. Only the one or more first narrowband analog RF signals may be analog-to-digital converted via the first subset of ADCs.

CLAIM OF PRIORITY

This patent application a continuation of U.S. patent application Ser.No. 14/570,640, filed on Dec. 15, 2014, which in turn makes referenceto, claims priority to and claims benefit from U.S. Provisional PatentApplication Ser. No. 61/940,127 filed Feb. 14, 2014. Each of the aboveidentified applications is hereby incorporated herein by reference inits entirety.

FIELD

The present disclosure generally relates to wireless communicationssystems. In particular, the present disclosure relates to a method andsystem for converting wideband analog radio frequency (RF) signals tothe digital domain in a multi band and multicarrier wirelesscommunications system.

BACKGROUND

Today's wireless communication systems generally use a single radiofrequency (RF) band, having a bandwidth anywhere from less than 5 MHz toover 200 MHz, to transmit and receive data. These wireless communicationsystems are generally capable of transmitting multiple RF carriers inone RF band.

The Federal Communications Commission (FCC) in the United States, andtheir equivalent organizations in other countries, continue to free upnew RF bands, which is creating new requirements for both industrystandards organizations, such as the 3rd Generation Partnership Project(3GPP) and cellular operators, for advanced wireless communicationsystems that can efficiently use these new RF bands.

Today's wireless communications standards generally utilize twomultiplexing techniques. For example, the GSM and CDMA standards utilizeFrequency Domain Duplex (FDD) multiplexing techniques. The WiFi andWiMAX standards utilize Time Domain Duplex (TDD) multiplexing techniquesand use a single RF carrier in one RF band. New developments in wirelesscommunications standards that use TDD multiplexing, such as WiFi(802.11ac) and Long-Term Evolution (LTE), specify the transmission andreception of data over multiple RF bands where each RF band has one ormore RF carriers. The multiple RF carriers may be contiguous in one RFband (i.e., intra band contiguous), non-contiguous in one RF band (i.e.,intra band non-contiguous,) or non-contiguous in two RF bands (i.e.,inter band non-continuous). FIG. 1A shows three contiguous RF carriersin a single RF band, or intra-band; FIG. 1B shows two contiguous RFcarriers and one non-contiguous RF carrier in a single RF band, orintra-band; and FIG. 10 shows two contiguous RF carriers in a first RFband and one RF carrier in a second non-contiguous RF band, orinter-band.

A “brute force” method that is typically used to adapt conventionalwireless communication systems to accommodate the requirements of newmulti-band wireless communications standards involves implementingseparate transceivers for each RF band and transmitting and receivingdata in each RF band using a single radio. The “brute force” method,however, limits the ability of an operator of the wirelesscommunications systems to manage power consumption of the radio.

Examples of known multiband and multicarrier wireless communicationsystems that are capable of transmitting and receiving data in two RFbands using one or more RF carriers are shown in FIG. 2A and FIG. 2B.FIG. 2A and FIG. 2B each show a conventional multiband and multicarrierwireless communication system 200 that includes a baseband unit 202connected to two separate RF transceivers 204, 206 by optical cables208, 210. The two RF transceivers 204, 206 are in turn connected to asingle multi-band antenna 212 by two RF coax cables 214, 216,respectively. The difference between conventional multiband andmulticarrier wireless communication system shown in FIG. 2A and the oneshown in FIG. 2B is that the two RF transceivers 204, 206 are packagedinto a single box 218 in the conventional multiband and multicarrierwireless communication system shown in FIG. 2.

Each RF transceiver in a conventional multiband and multicarrierwireless communication system, such as those shown in FIG. 2A and FIG.2B, includes analog-to-digital converters (ADCs) for converting RFsignals between the analog and digital domains, anddigital-to-analog-converters (DACs) for converting RF signals betweenthe digital and analog domains. When converting an analog signal to thedigital domain, to accurately represent that signal it must be sampledat a frequency between 2 to 5 times the bandwidth of the RF signal.Nyquist theory states that sampling at 2 times the bandwidth of the RFsignal is required; however often up to 5 times the bandwidth of theanalog RF signal is used in order to cancel out harmonics. Changes inwireless standards have resulted in wireless signals increasing inbandwidth that non-contiguously span intra-band and inter-band frequencyranges, requiring ADCs and DACs with increasing sampling rates. TheseADCs and DACs are expensive and inefficient in the use of electricalpower. Furthermore, the sampling rates of ADCs and DACs are unlikely tokeep pace with the demands placed upon them by the evolving wirelessstandards.

Improvements in the conversion of wideband analog RF signals to thedigital domain in multiband and multicarrier wireless systems aretherefore desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph illustrating power spectral density versus frequencyof three transmitted RF signals modulated on three contiguous carriersin a single RF band for a known multicarrier and multiband wirelesscommunication system.

FIG. 1B is a graph illustrating power spectral density versus frequencyof a three transmitted RF signals modulated on two contiguous carriersand one disjoint carrier in a single RF band for a known multicarrierand multiband wireless communication system.

FIG. 1C is a graph illustrating power spectral density versus frequencyof a two transmitted RF signals modulated on two contiguous carriers inone RF band and one transmitted RF signal modulated a carrier in anotherRF band known multicarrier and multiband wireless communication system.

FIGS. 2A and 2B are block diagrams of known multiband and multicarrierwireless communication systems.

FIG. 3 is a graph illustrating power spectral density versus frequencyof a wideband analog RF signal.

FIG. 4 is a flowchart illustrating a method of converting widebandanalog RF signals to the digital domain in accordance with an embodimentof the present disclosure.

FIG. 5 is a block diagram of an analog-to-digital conversion system forconverting analog radio frequency (RF) signals to the digital domain ina multiband and multicarrier wireless communications system inaccordance with an embodiment of the present disclosure.

FIG. 6 is a circuit diagram of an analog-to-digital conversion systemfor converting analog radio frequency (RF) signals to the digital domainin a multiband and multicarrier wireless communications system inaccordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

For simplicity and clarity of illustration, reference numerals may berepeated among the figures to indicate corresponding or analogouselements. Numerous details are set forth to provide an understanding ofthe embodiments described herein. The embodiments may be practicedwithout these details. In other instances, well-known methods,procedures, and components have not been described in detail to avoidobscuring the embodiments described. The description is not to beconsidered as limited to the scope of the embodiments described herein.Reference to specific elements of various embodiments of the presentdisclosure will now be made.

The present disclosure generally relates to a method and system forconverting wideband analog radio frequency (RF) signals between theanalog and digital domains.

The method of the present disclosure takes advantage of the differencebetween the sum of the bandwidths of narrowband analog RF signals thatmake up a wideband analog RF signal and the total bandwidth of thewideband analog RF signal, as shown in FIG. 3. FIG. 3 shows a graph ofthe power spectral density versus frequency of an example widebandanalog RF signal. The wideband analog RF signal 302 is made up of orincludes three narrowband analog RF signals 304, 306, 308. Thenarrowband analog RF signal 304 has a spectral range or bandwidth BWA,the narrowband analog RF signal 306 has a spectral range or bandwidthBWB, and the narrowband analog RF signal 308 has a spectral range orbandwidth BWC. The total occupied bandwidth of the three narrowbandanalog signals 304, 306, 308 is equal to the sum of BWA, BWB and BWC,and is always less that the total bandwidth of the wideband analog RFsignal 302.

The present disclosure provides a method and system that tracks theoccupied bandwidth of the narrowband analog RF signals that make up awideband analog RF signal rather than a total bandwidth of the widebandanalog RF signal.

A flowchart illustrating a method of converting wideband analog RFsignals to the digital domain according to an embodiment of the presentdisclosure is shown in FIG. 4. The method is performed by ananalog-to-digital conversion system that is implemented in a RFtransceiver of a multiband and multicarrier wireless communicationsystem.

The method begins at 400 and proceeds to step 405. At step 405, awideband analog RF signal is received. The wideband analog RF signalthat is received includes one or more narrowband analog RF signals. Eachnarrowband analog RF signal occupies a distinct non-overlapping spectralband within a spectrum of the wideband analog RF signal. After receivingwideband analog RF signal, the method proceeds to step 410. At step 410,the method analog-to-digital converts only the narrowband analog RFsignals occupying the distinct non-overlapping spectral bands, and themethods ends at step 415.

In an embodiment, the step 410 of analog-to-digital converting only thenarrowband RF analog signals occupying the distinct non-overlappingspectral bands includes separating the one or more narrowband analog RFsignals from the wideband analog RF signal.

In another embodiment, separating the one or more narrowband analog RFsignals from the wideband analog RF signal, which is part of step 410,includes down converting the first wideband analog RF signal to pairs oforthogonal baseband analog signals using a set of down conversionfrequencies, where each down conversion frequency is tuned to a centerof one of the distinct non-overlapping spectral bands, and filtering thepairs of orthogonal baseband analog signals to generate a set offiltered orthogonal analog baseband signals, each pair of filteredorthogonal analog baseband signals corresponding to one of the distinctnarrowband analog RF signals. In another embodiment, the step 410 ofanalog-to-digital converting includes converting each pair of filteredorthogonal analog baseband signals to a pair of digital signals.

In another embodiment, the step 410 of analog-to-digital convertingincludes converting each of the first pairs of filtered orthogonalbaseband analog signals to pairs of digital signals. In anotherembodiment, down converting includes amplifying each of the first pairsof orthogonal baseband analog signals. In still another embodiment,filtering includes filtering the first pairs of amplified orthogonalbaseband analog signals to generate the first pairs of filteredorthogonal baseband analog signals.

In another embodiment, the first pairs of orthogonal baseband signalseach include a first in-phase baseband signal and a first quadraturebaseband signal.

In another embodiment, the method includes, similar to step 405,receiving a second wideband analog RF signal comprising one or moresecond narrowband RF analog signals, each of the second narrowbandanalog RF signals occupying a distinct non-overlapping spectral bandwithin a spectrum of the second wideband analog RF signal, wherein thefirst and second wideband analog RF signals are spectrallynon-overlapping. The method further includes, similar to step 410,analog-to-digital converting only the second narrowband RF analogsignals occupying the distinct non-overlapping spectral bands within aspectrum of the second wideband analog RF signal.

In another embodiment, analog-to-digital converting only the secondnarrowband analog RF signals occupying the distinct non-overlappingspectral bands includes separating the one or more second narrowbandanalog RF signals from the second wideband analog RF signal.

In another embodiment, wherein separating the one or more secondnarrowband analog RF signals from the second wideband analog RF signalincludes down converting the second wideband analog RF signal to secondpairs of orthogonal baseband analog signals using a set of downconversion frequencies, where each down conversion frequency is tuned toa center of one of the distinct non-overlapping spectral bands, andfiltering the pairs of orthogonal baseband analog signals to generatepairs of filtered orthogonal baseband analog signals, each pair offiltered orthogonal baseband analog signals corresponding to one of thedistinct narrowband analog RF signals.

Referring now to FIG. 5, a block diagram of an analog-to-digitalconversion system 500 for converting wideband analog radio frequency(RF) signals to a digital domain according to an embodiment of thepresent disclosure. The analog-to-digital converter system 500 isimplemented in an RF transceiver of a multiband and multicarrierwireless and is configurable so that the system 500 can convert up to Nwideband analog RF signals to the digital domain. Each of the N widebandanalog RF signals can include one or more narrowband analog RF signals.Each of the narrowband analog RF signals occupies a distinctnon-overlapping spectral band within a spectral range of itscorresponding wideband analog RF signal.

The analog-to-digital conversion system 500 includes a firstcross-connect switch 502, N down converter modules 504, a secondcross-connect switch 506, and N analog-to-digital converters (ADCs) 508,where N is a positive integer. In an embodiment, the N ADCs aretime-interleaved ADCs.

The first cross-connect switch 502 includes N inputs for receivingwideband analog RF signals and N outputs. Each of the N outputs iselectrically connected to one of the N down converter modules 504. Thefirst cross-connect switch 502 is configurable to electrically connectany of the N inputs to one or more of the N down converter modules 504.Similarly, the second cross-connect 506 is configurable to electricallyconnect any one of the down converter modules 504 to one or more of theN ADCs 508. In an implementation, the cross connect switch 502 or 506can distribute a single input to multiple outputs.

In an embodiment, in operation, the first cross-connect 502 receives awideband analog RF signal that includes M narrowband analog RF signals,where M is a positive integer. Each of the M narrowband analog RFsignals occupies a distinct non-overlapping spectral band within aspectrum of the wideband analog RF signal. The first cross-connect 502is configured such that the wideband analog RF signal is output to Mdown converter modules 504. Each of the M down converter modules 504 istuned a center frequency of one of the distinct non-overlapping bands.The M down converter modules 504 divide or separate only the M analognarrowband RF signals from the wideband analog RF signal and output theM analog narrowband RF signals to a second cross-connect switch 506. Thesecond cross-connect switch 506 is configured to output each of the Manalog RF signals to an appropriate ADC module 508. Each appropriate ADCmodule 508 samples the narrowband analog RF signal it receives andoutputs a digital representation of the narrowband analog RF signal forpostprocessing into a single digital signal that represent the originalwideband analog RF signal.

In an embodiment, ADC modules 508 may be enabled and disabled so thatonly those ADC modules 508 necessary for converting a wideband analog RFsignal are enabled.

FIG. 6 shows a circuit diagram of an analog-to-digital converter system600 for converting wideband analog signals to the digital domainaccording to an embodiment of the present disclosure. Theanalog-to-digital converter system 600 is implemented in an RFtransceiver of a multiband and multicarrier wireless communicationsystem and is configurable so that the system 600 can convert up to twowideband analog RF signals to the digital domain. Each of the twowideband analog RF signals can include either one narrowband analog RFsignal or two narrowband analog RF signals, where each of the narrowbandanalog RF signals occupies a distinct non-overlapping spectral bandwithin a spectral range of the wideband analog RF signal.

The system 600 includes a first amplifier 602 and a second amplifier604. The first amplifier 602 has a pair of inputs 606 a, 606 b forreceiving a first wideband analog RF signal and an output that iselectrically connected by 608 to a first input of a first cross-connect610. The second amplifier 604 also has a pair of inputs 612 a, 612 b forreceiving a second wideband analog RF signal and an output that iselectrically connected by 614 to a second input of the firstcross-connect 610. In the example embodiment shown in FIG. 6, the firstand second wideband analog RF signals are each differential analog RFsignals.

The first cross-connect 610 also has a first output that is electricallyconnected by 616 to a first input of a first down converter module 618and a second output that is electrically connected by 620 to a firstinput of a second down converter module 622. The first cross-connect 610is configurable to electrically connect the output of the firstamplifier 602 to: (1) the first input of the first down converter module618; (2) the first input of the second down converter module 622; or (3)the first input of both the first and second down converter modules 618,622. Similarly, the first cross-connect 610 is configurable toelectrically connect the output of the second amplifier 604 to: (1) theinput of the first down converter module 618; (2) the first input seconddown converter module 622; or (3) the first inputs of both the first andsecond down converter modules 620, 624. Thus, the first down convertermodule 618 is capable of receiving the wideband analog RF signal fromthe output of the first amplifier 602 or the second wideband analog RFsignal from the output of the second amplifier 604, depending on theconfiguration of the first cross-connect 610. Also, the second downconverter module 618 is capable of receiving the wideband analog RFsignal from the output of the first amplifier 602 or the second widebandanalog RF signal from the output of the second amplifier 604, againdepending on the configuration of the first cross-connect 610.

Referring again to FIG. 6, the system 600 also includes a first localoscillator 624 for generating a first local oscillator signal and asecond local oscillator 626 for generating a second oscillator signal.The first and second local oscillators 624, 626 are electricallyconnected by 628, 630, respectively, to a local oscillator selector 632.The local oscillator selector 632 is configurable to electricallyconnect, by 634, one of the first oscillator signal generated by thefirst local oscillator 624 and the second oscillator signal generated bythe second local oscillator 626 to a second input of the first downconverter module 618. The local oscillator selector 632 is alsoconfigurable to electrically connect, by 636, one of the firstoscillator signal generated the first local oscillator 624 and thesecond oscillator signal generated by the second local oscillator 626 toa second input of the second down converter module 622.

The first down converter module 618 includes a first pair of mixers 638a, 638 b, a first pair of amplifiers 640 a, 640 b, a first pair offilters 642 a, 642 b, and a first phase shifter 644. The first phaseshift generator 644 receives, by 634, one of the first and second localoscillator signals from the local oscillator selector 632, generates afirst in-phase signal and a first quadrature signal from the one of thefirst and second local oscillator signals, and provides the in-phase andquadrature signals to the mixers 638 a, 638 b, respectively.

Similarly, the second down converter module 622 includes a second pairof mixers 646 a, 646 b, a second pair of amplifiers 648 a, 648 b, asecond pair of filters 650 a, 650 b and a second phase shifter 652. Thesecond phase shift generator 652 receives by 636, one of the first andsecond local oscillator signals from the local oscillator selector 632,generates a second in-phase signal and a second quadrature signal fromthe one of the first and second local oscillator signals, and providesthe in-phase and quadrature signals to the mixers 648 a, 648 b,respectively.

The first pair of filters 642 a, 642 b is electrical connected to afirst pair of inputs of a second cross-connect 654. Similarly, a pair ofoutputs of the second pair of filters 650 a, 650 b is electricallyconnected to a second pair of inputs of the second cross-connect 654.

The second cross-connect 654 has a first pair of outputs electricallyconnected to a first pair of analog-to-digital converters 656 a, 656 band a second pair of outputs electrically connected to a second pair ofanalog-to-digital converters 658 a, 658 ab. The second cross-connect 654is configurable to connect any of the first pair of filters 642 a, 642 band the second pairs of filters 652 a, 652 b to any of the first pair ofanalog-to-digital converters 656 a, 656 b and the second pair ofanalog-to-digital converters 658 a, 658 b, respectively. Each pair ofanalog-to-digital converters, 656 a, 656 b and 658 a, 658 b, iselectrically connected, by 660, to a clock generator 662 for receiving aclock signal that has a frequency of two to five times the bandwidth ofany of the narrowband analog RF signal occupying the distinctnon-overlapping spectral bands.

An example of the operation of the analog-to-digital converter system600 will now be described. In this example, the analog-to-digitalconversion system 600 receives only one wideband analog RF signal thatincludes two narrowband analog RF signals. A first narrowband analog RFsignal of the two narrowband analog RF signals occupies a firstnon-overlapping spectral band within a spectrum of the first widebandanalog RF signal. A second narrowband analog RF signal of the twonarrowband analog RF signals that occupies a second non-overlappingspectral band within a spectrum of the first wideband analog RF signal.

The first cross-connect 610 is configured to electrically connect theoutput of the first amplifier 602 to the first input of the first downconverter module 618 and to the first input of the second down convertermodule 622. The second cross-connect 654 is configured such that itsfirst pair of outputs is electrically connected to the first pair ofanalog-to-digital converters 656 a, 656 b and its second pair of outputsis electrically connected to the second pair of analog-to-digitalconverters 658 a, 658 b.

The local oscillator selector 632 is configured to electrically connect,by 634, the first clock signal generated by the first local oscillator624 to the input of the first phase shifter 644 of the first downconverter module 618 and to electrically connect, by 636, the secondclock signal generated by the second local oscillator 626 to the inputof the second phase shifter 652 of the second down converter module 622.The first local oscillator 624 is tuned to a center frequency of thefirst non-overlapping spectral band and the second local oscillator 626is tuned to a center frequency of the second non-overlapping spectralband.

In operation, the first amplifier 602 receives the first wideband analogRF signal and amplifies the first wideband analog RF signal. Theamplified first wideband analog RF signal is then provided by the firstcross-connect 610 to both the first and second down converter modules618, 622 to separate the first and second narrowband analog RF signalsfrom the first wideband analog RF signal. The first and secondnarrowband analog RF signals are separated from the wideband analog RFsignal as follows. The first down converter module 618 receives thefirst wideband analog RF from the first amplifier 602 via 608, 616. Afirst mixer 638 a of the first pair of mixers 638 a, 638 b multipliesthe first wideband analog RF signal with the first in-phase signalreceived from the first phase shifter 644 to generate a first in-phasebaseband signal. A second mixer 638 b of the first pair of mixers 638 a,638 b also multiplies the first wideband analog RF signal with the firstquadrature signal received from the first phase shifter 644 to generatea first quadrature baseband signal. The first in-phase baseband signaland first quadrature baseband signal together form a first pair oforthogonal baseband signals.

The second down converter module 622 receives the first wideband analogRF from the second amplifier 604 via 614, 620. A first mixer 646 a ofthe second pair of mixers 646 a, 646 b multiplies the first widebandanalog RF signal with the second in-phase signal received from thesecond phase shifter 652 to generate a second in-phase baseband signal.A second mixer 646 b of the second pair of mixers 646 a, 646 b alsomultiplies the first wideband analog RF signal with the secondquadrature signal received from the second phase shifter 652 to generatea second quadrature baseband signal. The second in-phase and secondquadrature baseband signals together form a second pair of orthogonalbaseband signals.

The first pair of orthogonal baseband signals is provided by the firstpair of mixers 638 a, 638 b to the first pair of amplifiers 640 a, 640b. The first pair of amplifiers 640 a, 640 b amplify the first pair oforthogonal baseband signals and provide the first pair of amplifiedorthogonal baseband signals to the first pair of filters 642 a, 642 b,which filter or separate the first pair of amplified orthogonal basebandsignals corresponding to the first narrowband analog RF signal occupyingthe first non-overlapping spectral band. The first pair of filteredorthogonal baseband signals includes a first filtered in-phase basebandanalog signal and a first filtered quadrature baseband analog signal.The first pair of filtered orthogonal baseband signals is provided bythe first pair of filters 642 a, 642 b to the first pair of inputs ofthe second cross-connect 654.

Similarly, the second pair of orthogonal baseband signals is provided bythe second pair of mixers 646 a, 646 b to the first pair of amplifiers648, 648 b. The second pair of amplifiers 648 a, 648 b amplify thesecond pair of orthogonal baseband signals and provide the second pairof amplified orthogonal baseband signals to the second pair of filters650 a, 650 b, which filter out or separate the second pair of amplifiedorthogonal baseband signals corresponding to the second narrowbandanalog RF signal occupying the second non-overlapping spectral bandwithin the spectrum of the first wideband analog RF signal. The secondpair of filtered orthogonal baseband signals includes a second filteredin-phase baseband analog signal and a second filtered quadraturebaseband analog signal. The second pair of filtered orthogonal basebandsignals are provided by the second pair of filters 650 a, 650 b to thesecond pair of inputs of the second cross-connect 654.

The first pair of inputs of the second cross-connect 654 areelectrically connected to the first pair of ADCs 656 a, 656 b and thesecond pair of inputs of the second cross-connect 654 are connected tothe second pair of ADCs 658 a, 658 b. The first pair of ADCs 656 a, 656b receives the first pair of filtered baseband orthogonal signals andconverts the first pair of filtered baseband orthogonal signals to afirst pair of digital signals using the clock signal provided on 660 bythe clock generator 662. Similarly, the second pair of ADCs 658 a, 658 breceives the second pair of filtered orthogonal baseband signals andconverts the second pair of filtered orthogonal baseband signals to asecond pair of digital signals using the clock signal provided on 660 bythe clock generator 662. Both the first and second pair of digitalsignals are provided by the analog-to-digital conversion system 600 forfurther processing as is known in the art. The clock signal provided byon 660 the clock generator 662 samples the first and second pairs offiltered baseband orthogonal signals at two to five times the bandwidthof the first and second non-overlapping spectral bands, respectively.

Another example of the operation of the analog-to-digital convertersystem 600 will now be described. In this example, the analog-to-digitalconversion system 600 receives two wideband analog RF signals, whereeach wideband analog RF signal includes one narrowband analog RF signal.A first narrowband analog RF signal occupies a first non-overlappingspectral band within a spectrum of the first wideband analog RF signaland a second narrowband analog RF signal occupies a secondnon-overlapping spectral band within a spectrum of the second widebandanalog RF signal.

The first cross-connect 610 is configured to electrically connect theoutput of the first amplifier 602 to the first input of the first downconverter module 618 and to electrically connect the output of thesecond amplifier 604 to the first input of the second down convertermodule 622. The second cross-connect 654 is configured such that itsfirst pair of outputs are electrically connected to the first pair ofanalog-to-digital converters 656 a, 656 b and its second pair of outputsis electrically connected to the second pair of analog-to-digitalconverters 658 a, 658 b.

The local oscillator selector 632 is configured to electrically connect,by 634, the first clock signal generated by the first local oscillator624 to the input of the first phase shifter 644 of the first downconverter module 618 and to electrically connect, by 636, the secondclock signal generated by the second local oscillator 626 to the inputof the second phase shifter 652 of the second down converter module 622.The first local oscillator 624 is tuned to a center frequency of thefirst non-overlapping spectral band and the second local oscillator 626is tuned to a center frequency of the second non-overlapping spectralband.

In operation, the first amplifier 602 receives the first wideband analogRF signal and amplifies the first wideband analog RF signal. The firstamplified wideband analog RF signal is then provided by the firstcross-connect 610 to the first converter module 618 to separate thefirst narrowband analog RF signal from the first wideband analog RFsignal. The second amplifier 604 receives the second wideband analog RFsignal. The second amplified wideband analog RF signal amplifies is theprovided by the first cross-connect 610 to the second converter module622 to separate the second narrowband analog RF signal from the secondwideband analog RF signal.

The first and second narrowband analog RF signals are separated from thefirst and second wideband analog RF signals, respectively, as follows.The first down converter module 618 receives the first amplifiedwideband analog RF from the first amplifier 602 via 608, 616. A firstmixer 638 a of the first pair of mixers 638 a, 638 b multiplies thefirst wideband analog RF signal with the first in-phase signal receivedfrom the first phase shifter 644 to generate a first in-phase basebandsignal. A second mixer 638 b of the first pair of mixers 638 a, 638 balso multiplies the first amplified wideband analog RF signal with thefirst quadrature signal received from the first phase shifter 644 togenerate a first quadrature baseband signal. The first in-phase andfirst quadrature baseband signals together form a first pair oforthogonal baseband signals.

The second down converter module 622 receives the second amplifiedwideband analog RF from the second amplifier 604 via 614, 620. A firstmixer 646 a of the second pair of mixers 646 a, 646 b multiplies thesecond amplified wideband analog RF signal with the second in-phasesignal received from the second phase shifter 652 to generate a secondin-phase baseband signal. A second mixer 646 b of the second pair ofmixers 646 a, 646 b also multiplies the second amplified wideband analogRF signal with the second quadrature signal received from the secondphase shifter 652 to generate a second quadrature baseband signal. Thesecond in-phase and second quadrature baseband signals together form asecond pair of orthogonal baseband signals.

The first pair of orthogonal baseband signals is provided by the firstpair of mixers 538 a, 538 b to the first pair of amplifiers 640 a, 640b. The first pair of amplifiers 640 a, 640 b amplify the first pair oforthogonal baseband signals and provide the first pair of amplifiedorthogonal baseband signals to the first pair of filters 642 a, 642 b,which filter or separate the first pair of amplified orthogonal basebandsignals corresponding to the first narrowband analog RF signal occupyingthe first non-overlapping spectral band within the spectrum of the firstwideband analog RF signal. The first pair of filtered orthogonalbaseband signals includes a first filtered in-phase baseband analogsignal and a first filtered quadrature baseband analog signal. The firstpair of filtered orthogonal baseband signals is provided by the firstpair of filters 642 a, 642 b to the first pair of inputs of the secondcross-connect 654.

Similarly, the second pair of orthogonal baseband signals is provided bythe second pair of mixers 646 a, 646 b to the first pair of amplifiers648, 648 b. The second pair of amplifiers 648 a, 648 b amplify thesecond pair of orthogonal baseband signals and provide the second pairof amplified orthogonal baseband signals to the second pair of filters650 a, 650 b, which filter out or separate the second pair of amplifiedorthogonal baseband signals corresponding to the second narrowbandanalog RF signal occupying the second non-overlapping spectral bandwithin the spectrum of the second wideband analog RF signal. The secondpair of filtered orthogonal baseband signals includes a second filteredin-phase baseband analog signal and a second filtered quadraturebaseband analog signal. The second pair of filtered orthogonal basebandsignals are provided by the second pair of filters 650 a, 650 b to thesecond pair of inputs of the second cross-connect 654.

The first pair of inputs of the second cross-connect 654 areelectrically connected to the first pair of ADCs 656 a, 656 b and thesecond pair of inputs of the second cross-connect 654 are connected tothe second pair of ADCs 658 a, 658 b. The first pair of ADCs 656 a, 656b receives the first pair of filtered baseband orthogonal signals andcoverts the first pair of filtered baseband orthogonal signals to afirst pair of digital signals using the clock signal provided on 660 bythe clock generator 662. Similarly, the second pair of ADCs 658 a, 658 breceives the second pair of filtered orthogonal baseband signals andconverts the second pair of filtered orthogonal baseband signals to asecond pair of digital signals using the clock signal provided on 660 bythe clock generator 662. Both the first and second pair of digitalsignals are provided by the analog-to-digital conversion system 600 forfurther processing as is known in the art. The clock signal provided bythe clock generator 662 samples the first and second pairs of filteredbaseband orthogonal signals at two to five times the bandwidth of thefirst and second non-overlapping spectral bands, respectively.

Advantageously, the method and system of the present disclosure enable asingle RF transceiver to efficiently convert wideband analog RF signalsbetween the analog and digital domains. In an embodiment, theanalog-to-digital converters of the single RF transceiver track theoccupied bandwidth of a plurality of narrowband analog RF signals ratherthan a total bandwidth of the wideband analog RF signal. This enablesthe system of the present disclosure to have a smaller form factor, toconsume less power, and to be cheaper to manufacture than the knownsystems used in multiband and multicarrier receivers.

Embodiments of the disclosure may be represented as a computer programproduct stored in a machine-readable medium (also referred to as acomputer-readable medium, a processor-readable medium, or a computerusable medium having a computer-readable program code embodied therein).The machine-readable medium can be any suitable tangible, non-transitorymedium, including magnetic, optical, or electrical storage mediumincluding a diskette, compact disk read only memory (CD-ROM), memorydevice (volatile or non-volatile), or similar storage mechanism. Themachine-readable medium can contain various sets of instructions, codesequences, configuration information, or other data, which, whenexecuted, cause a processor to perform steps in a method according to anembodiment of the disclosure. Those of ordinary skill in the art willappreciate that other instructions and operations necessary to implementthe described implementations may also be stored on the machine-readablemedium. The instructions stored on the machine-readable medium may beexecuted by a processor or other suitable processing device, and mayinterface with circuitry to perform the described tasks.

The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the claims should not belimited by the preferred embodiments set forth in the examples, butshould be given the broadest interpretation consistent with thedescription as a whole. All changes that come with meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A method comprising: receiving a first widebandanalog RF signal, wherein: the first wideband analog RF signal comprisesone or more first narrowband analog RF signals, and a total ofbandwidths of the one or more first narrowband analog RF signals is lessthan a total bandwidth of the first wideband analog RF signal; selectinga first subset of analog-to-digital converters (ADCs) from a pluralityof analog-to-digital converters (ADCs), wherein a number of ADCs in thefirst subset of ADCs is less than a total number of ADCs in theplurality of ADCs; enabling only the first subset of ADCs, such that allremaining ADCs in the plurality of ADCs are not enabled; andanalog-to-digital converting, via the first subset of ADCs, only to theone or more first narrowband analog RF signals, such that a remainder ofthe first wideband analog RF signal is not converted.
 2. The method ofclaim 1, comprising separating the one or more first narrowband analogRF signals from the first wideband analog RF signal, wherein theseparating comprises: down-converting the first wideband analog RFsignal to first pairs of orthogonal baseband analog signals using a setof down-conversion frequencies, wherein each down-conversion frequencyis tuned to a center frequency of one of the distinct non-overlappingspectral bands; and filtering the first pairs of orthogonal basebandanalog signals to generate first pairs of filtered orthogonal basebandanalog signals, each of the first pairs of filtered orthogonal basebandanalog signals corresponding to one of the distinct narrowband analog RFsignals.
 3. The method of claim 2, wherein the analog-to-digitalconverting comprises converting each of the first pairs of filteredorthogonal baseband analog signals to pairs of digital signals.
 4. Themethod of claim 2, wherein the down-converting comprises amplifying eachof the first pairs of orthogonal baseband analog signals.
 5. The methodof claim 4, wherein the filtering comprises filtering the first pairs ofamplified orthogonal baseband analog signals to generate the first pairsof filtered orthogonal baseband analog signals.
 6. The method of claim2, wherein the first pairs of orthogonal baseband signals comprise afirst in-phase baseband signal and a first quadrature baseband signal.7. The method of claim 1, comprising: receiving a second wideband analogRF signal, wherein: the second wideband analog RF signal comprises oneor more second narrowband RF analog signals, and the first and secondwideband analog RF signals are spectrally non-overlapping; and selectinga second subset of analog-to-digital converters (ADCs) from theplurality of ADCs to perform analog-to-digital conversion of only theone or more second narrowband RF analog signals; and enabling only thesecond subset of ADCs, such that each remaining ADC in the plurality ofADCs outside of the first and second subsets is not enabled.
 8. Themethod of claim 7, wherein the analog-to-digital converting of only theone or more second narrowband analog RF signals comprises separating theone or more second narrowband analog RF signals from the second widebandanalog RF signal.
 9. The method of claim 8, wherein the separating ofthe one or more second narrowband analog RF signals from the secondwideband analog RF signal comprises: down-converting the second widebandanalog RF signal to second pairs of orthogonal baseband analog signalsusing a set of down-conversion frequencies, wherein each down-conversionfrequency is tuned to a center frequency of one of the distinctnon-overlapping spectral bands; and filtering the second pairs oforthogonal baseband analog signals to generate pairs of filteredorthogonal baseband analog signals, wherein each pair of filteredorthogonal baseband analog signals corresponding to one of the distinctnarrowband analog RF signals.
 10. A system comprising: a first receivingcircuit operable to receive a first wideband analog RF signal, wherein:the first wideband analog RF signal comprises one or more firstnarrowband analog RF signals; and a total of bandwidths of the one ormore first narrowband analog RF signals is less than a total bandwidthof the first wideband analog RF signal; a plurality of analog-to-digitalconverters (ADCs); and a controller circuit operable to: select a firstsubset of analog-to-digital converters (ADCs) from the plurality ofADCs, wherein a number of ADCs in the first subset of ADCs is less thana total number of ADCs in the plurality of ADCs; and enable only thefirst subset of ADCs, such that all remaining ADCs in the plurality ofADCs are not enabled; wherein the first subset of ADCs is operable toanalog-to-digital convert only the one or more first narrowband analogRF signals, such that a remainder of the first wideband analog RF signalis not converted.
 11. The system of claim 10, comprising one or moredown-converters, wherein each down-converter being tunable to aparticular down-conversion frequency, the one or more down-convertersare operable to down-convert the first wideband analog RF signal tofirst pairs of orthogonal baseband analog signals using a set ofdown-conversion frequencies, wherein each down-conversion frequency istuned to a center frequency of one of the distinct non-overlappingspectral bands.
 12. The system of claim 11, comprising one or morefilters operable to filter the first pairs of orthogonal baseband analogsignals to generate first pairs of filtered orthogonal baseband analogsignals, wherein each of the first pairs of filtered orthogonal basebandanalog signals corresponding to one of the distinct narrowband analog RFsignals.
 13. The system of claim 12, wherein the first subset of ADCs isoperable to, when analog-to-digital converting the one or more firstnarrowband analog RF signals, convert each of the first pairs offiltered orthogonal baseband analog signals to pairs of digital signals.14. The system of claim 12, comprising one or more amplifiers operableto amplify each of the first pairs of orthogonal baseband analog signalsto generate first pairs of amplified orthogonal baseband analog signals.15. The system of claim 14, wherein the one or more down-converters areoperable to filter the first pairs of amplified orthogonal basebandanalog signals to generate the first pairs of filtered orthogonalbaseband analog signals.
 16. The system of claim 10, comprising: asecond receiving circuit operable to receive a second wideband analog RFsignal, wherein: the second wideband analog RF signal comprises one ormore second narrowband RF analog signals, and the first and secondwideband analog RF signals are spectrally non-overlapping; and whereinthe controller circuit is operable to: select a second subset ofanalog-to-digital converters (ADCs) from the plurality of ADCs toanalog-to-digital convert only the one or more second narrowband RFanalog signals; and enable only the second subset of ADCs, such thateach remaining ADC in the plurality of ADCs outside of the first andsecond subsets is not enabled.
 17. The system of claim 16, comprisingone or more down-converters, wherein each down-converter being tunableto a particular down-conversion frequency, the one or moredown-converters are operable to down-convert the second wideband analogRF signal to second pairs of orthogonal baseband analog signals using aset of down-conversion frequencies, wherein each down-conversionfrequency is tuned to a center frequency of one of the distinctnon-overlapping spectral bands.
 18. The method of claim 17, comprisingone or more filters operable to filter the second pairs of orthogonalbaseband analog signals to generate pairs of filtered orthogonalbaseband analog signals, wherein each pair of filtered orthogonalbaseband analog signals corresponding to one of the distinct narrowbandanalog RF signals.
 19. The system of claim 10, comprising a connectingcircuit operable to connect one or more of the plurality of ADCs to anyone or more other circuits in the system.
 20. The system of claim 19,wherein the connecting circuit is operable to connect one or more of theplurality of ADCs to any one of a plurality of down-converters toanalog-to-digital convert only the first narrowband analog RF signalsoccupying the distinct non-overlapping spectral bands while notanalog-to-digital converting the remainder of the first wideband analogRF signal.